Avoid creating duplicate players when switching from cast to local.


git-svn-id: svn://svn.code.sf.net/p/subsonic/code@4071 104adb81-38d2-4886-885e-82898e39ce25
Set X-Content-Duration to support opus encoding.


git-svn-id: svn://svn.code.sf.net/p/subsonic/code@4072 104adb81-38d2-4886-885e-82898e39ce25